Utility of simultaneously acquired gradient-echo and spin-echo cerebral blood volume and morphology maps in brain tumor patients

Donahue, Kathleen M.; Krouwer, Hendrikus G. J.; Rand, Scott D.; Pathak, Arvind P.; Marszalkowski, Cathy S.; Censky, Steven C.; Prost, Robert

doi:10.1002/1522-2594(200006)43:6<845::aid-mrm10>3.0.co;2-j

Cited by 215 publications

(146 citation statements)

References 23 publications

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“…[4,5]. The above property is weakly violated by the water exchange through the capillary walls, a process that is not taken into account in the present study.…”

Section: Contribution Of Intravascular Spinsmentioning

confidence: 84%

“…In particular, these equations neglect the intravascular signal, the native blood paramagnetism, a depart from the static regime of spin dephasing around capillaries, and the echo time dependence of the relaxation rates in Eqs. [4] and [5]. The effects of these factors are discussed in this section.…”

Section: Theoretical Resultsmentioning

confidence: 99%

“…Generically, Eqs. [4] and [5] define the scaling rules for the parameters entering the function arguments.…”

Section: Relaxation Of Signal From Extravascular Protonsmentioning

confidence: 99%

“…It becomes monoexponential only for large values of their arguments in Eqs. [4] and [5], the limit in which the main equations Eqs. [12] and [11] are obtained.…”

Section: Effect Of Echo-time-dependent Relaxation Ratesmentioning

confidence: 99%

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Vessel size imaging in humans

Kiselev

Strecker

Ziyeh

et al. 2005

Magnetic Resonance in Med

185

286

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The relation of contrast-enhanced transverse relaxation rates R 2 * and R 2 provides in vivo mapping of the mean caliber of cerebral vessels. This technique is referred to as vessel size imaging (VSI) The microvasculature, which includes the smallest and intermediate vessels, cannot be imaged directly with current MRI techniques. MRI examinations yield averaged microvasculature-related characteristics of perfusion or pharmacokinetics. Recently, attempts have been made to measure the mean vessel caliber in vivo (1, 2) in animal models. The feasibility of such measurements is granted by the difference in the contributions of small vessels to the transverse relaxation rates of the free induction decay, R* 2 , and that of the spin echo (SE), R 2 , (3-7) (Fig. 1). The method is based on measuring the changes in both rates, ⌬R* 2 and ⌬R 2 , after administration of a paramagnetic contrast agent. The average vessel size in a tissue can be estimated from ⌬R* 2 and ⌬R 2 according to theoretical predictions provided either by Monte Carlo simulations (2, 3) or by analytical modeling (4,8,9)..A quantitative assessment of the microvasculature might have diagnostic impact on the differential diagnosis of intracranial tumors. In a recent study (5) a correlation was found between glioma grade and regional cerebral blood volume (rCBV) measured with a gradient echo (GE) technique, while SE data showed no significant correlation. This result was qualitatively explained by the higher sensitivity of R* 2 to large vessels, which are inherent to malignant tumor tissues. Similarly, it was reported (6, 7) that the difference in regional blood volume assessed with GE and SE techniques increases for high-grade brain tumors.In the present study, quantitative imaging of the mean vessel caliber was performed in brain tumor patients undergoing routine MRI examinations. Previous experiments were performed in animals (2) using an intravascular contrast agent (USPIO) and monitoring its blood concentration invasively. The present method has been developed to meet the conditions of human studies in a clinical environment, in particular, the transient character of the contrast enhancement during the first bolus passage. The analysis presented and computer simulations help to understand the restrictions of the method and its shortcomings, which are caused by the complex relationship between the microvascular morphology and the measured NMR signal. Four illustrative cases of brain tumors are discussed in the context of the model developed.

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“…[4,5]. The above property is weakly violated by the water exchange through the capillary walls, a process that is not taken into account in the present study.…”

Section: Contribution Of Intravascular Spinsmentioning

confidence: 84%

Section: Theoretical Resultsmentioning

confidence: 99%

“…Generically, Eqs. [4] and [5] define the scaling rules for the parameters entering the function arguments.…”

Section: Relaxation Of Signal From Extravascular Protonsmentioning

confidence: 99%

“…It becomes monoexponential only for large values of their arguments in Eqs. [4] and [5], the limit in which the main equations Eqs. [12] and [11] are obtained.…”

Section: Effect Of Echo-time-dependent Relaxation Ratesmentioning

confidence: 99%

See 2 more Smart Citations

Vessel size imaging in humans

Kiselev

Strecker

Ziyeh

et al. 2005

Magnetic Resonance in Med

185

286

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“…When contrast enhancement was present, correction of rCBV for potential agent extravasations was investigated as proposed by Donahue et al (19), but not retained since similar results were obtained with or without correction.…”

Section: Data Analysis and Image Postprocessingmentioning

confidence: 99%

Correlations between MR and endothelial hyperplasia in low‐grade gliomas

Callot

Galanaud

Figarella‐Branger

et al. 2007

Magnetic Resonance Imaging

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Purpose:To investigate the capacity of multimodal MR to detect endothelial hyperplasia (EH), which has been linked to the aggressiveness of gliomas and which is so far only detected by biopsy, an invasive technique that prevents repeated measurements and early detection. Materials and Methods:A total of 26 patients with lowgrade gliomas participated in the study. All underwent a histopathological analysis and a multimodal MR examination (spectroscopic, anatomic, diffusion, perfusion, and postcontrast imaging).Results: EH was present (EHϩ) in 15 patients and absent (EH-) in 11. No differences were observed between EH-and EHϩ groups when comparing spectroscopic and diffusion parameters. Perfusion measurements, however, allowed us to distinguish EHϩ from EH-: the relative regional cerebral blood flow (rCBF) was found equal to 3.23 Ϯ 2.05 for EHϩ and 1.33 Ϯ 0.46 for EH-(P ϭ 0.006). Conclusion:We have observed a strong correlation between the presence of EH and the increase of rCBF. Compared to conventional imaging, MR perfusion provides additional and complementary information that may be used for biopsy guidance, early detection of tumor aggressiveness, and noninvasive follow-ups.

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Novel Imaging Agents for Molecular MR Imaging of Cancer

Artemov

Bhujwalla

2005

Drug Discovery Handbook

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Utility of simultaneously acquired gradient-echo and spin-echo cerebral blood volume and morphology maps in brain tumor patients

Cited by 215 publications

References 23 publications

Vessel size imaging in humans

Vessel size imaging in humans

Correlations between MR and endothelial hyperplasia in low‐grade gliomas

Novel Imaging Agents for Molecular MR Imaging of Cancer

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